The present invention relates to liquid level detection; and, more particularly, to liquid level detection gauges that utilize radio-frequency (RF) transmissions.
Measuring ink levels inside ink tanks and ink-cartridges has been attempted utilizing several methods including: electrical resistance, capacitance and optical methods. Most of these prior methods require modifications to the ink cartridges such as adding electrodes or optical windows to the ink cartridges. Such modifications are not always desirable in the printing industry. Electrodes added to the inner surfaces of the cartridge can corrode over time. Optical methods have been successfully utilized in ink tanks, but not as successfully in foam reservoirs. Accordingly, a simple method that detects the amount of ink in ink tanks and cartridges is desirable.